REVOLUTE GEOMETRY – 21116

Industrial robot arms can move in various different ways, depending on their intended use. One mode of movement is known as revolute geometry.

The illustration shows a robot arm capable of moving in three dimensions (3-D) using revolute geometry.The entire assembly can rotate through a full circle (360°) at the base. There is an elevation joint, or “shoulder,” that can move the arm through 90°, from horizontal to vertical. One or two joints in the middle of the robot arm, called “elbows,” can move through 180°, from a straight position to doubled back.As an option, there can be a “wrist” that freely rotates either clockwise or counterclockwise.

A well-designed revolute robot arm can reach any point within a halfsphere having the shape of an inverted bowl. The radius of the half-sphere is the length of the arm when its shoulder and elbow(s) are straightened out.